<!DOCTYPE HTML>
<html>
<head>
    <title>My WebSocket</title>
</head>
<meta charset="UTF-8" />
<body>
<div>
    <input type="text" id="content" placeholder="请输入...">
</div>
<button type="submit" onclick="submit()">发送</button>
<div id="message"></div>
</body>

<script type="text/javascript">
    let websocket = null;

    //判断当前浏览器是否支持WebSocket
    if ('WebSocket' in window) {
        websocket = new WebSocket("ws://localhost:8080/websocket/test01");
    } else {
        alert('Not support websocket')
    }

    //连接发生错误的回调方法
    websocket.onerror = function () {
        setMessageInnerHTML("error");
    };

    //连接成功建立的回调方法

    websocket.onopen = function (event) {
        setMessageInnerHTML("open");
    }

    //接收到消息的回调方法
    websocket.onmessage = function (event) {
        let data = event.data
        console.log(data);
        setMessageInnerHTML(event.data);
    }

    //连接关闭的回调方法
    websocket.onclose = function () {
        setMessageInnerHTML("close");
    }

    //监听窗口关闭事件，当窗口关闭时，主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。
    window.onbeforeunload = function () {
        websocket.close();
    }

    //将消息显示在网页上
    function setMessageInnerHTML(innerHTML) {
        document.getElementById('message').innerHTML += innerHTML + '<br/>';
    }

    //关闭连接
    function closeWebSocket() {
        websocket.close();
    }

    function submit() {
        let value = document.getElementById('content').value;
        websocket.send(value);
        return false;
    }
</script>
</html>